The U.S. space agency has big plans for the Red Planet. NASA has announced an ambitious multi-year Mars exploration program, looking ahead to meeting President Barack Obama's challenge to send humans to Mars in the 2030s.

NASA administrator Charles Bolden said the seven missions, planned or already under way, will ensure America remains the world leader in the exploration of our Earth-like neighbor. Next year, NASA will send an orbiter to study the Martian upper atmosphere, and in later years, another mission will take the first look into the planet's deep interior.

The line drawn on this map shows the route that NASA's Mars Exploration Rover Opportunity has driven. Opportunity has been working on Mars since January 2004, at sites within the Meridiani Planum region. (NASA/JPL/Cornell/University of Arizona)

American space scientists also will work with the European Space Agency's 2016 and 2018 ExoMars missions. In addition, a new rover is planned for launch in 2020, building on the successful design of Curiosity.

The car-sized robotic vehicle Curiosity currently is traversing the Martian landscape, digging through the Martian soil for any evidence there may have been life on that planet, and is four months into its two-and-a-half-year mission. NASA's Mars Exploration Rover Opportunity has been working on Mars since January 2004.

The planned new rover would be a new addition to NASA's ambitious program of exploring the Martian surface and atmosphere, ahead of its goal to send a manned mission to the Red Planet in about 20 years.